The present invention relates to a drive assembly for a moveable vehicle component of a vehicle, which component can adopt one or more positions in which the component prevents access to the vehicle or a part of the vehicle. The drive assembly comprises an actuator, which is coupled to the component and provides the force for moving the component, and a control unit for controlling the actuator. The drive assembly has an emergency operating mode, in which the actuator can move freely in at least one direction, in such a manner that the actuator allows movement of the component caused by an external force being exerted on the component other than by the actuator, preferably by hand. The drive assembly also is provided with theft detection means for detecting theft and/or attempted theft of the vehicle and/or of goods which are present in the vehicle, and the theft detection means is coupled to the control unit. The invention also relates to a method for preventing unauthorized access to a part of a vehicle.
A drive assembly is known, for example, from DE 38 26 789, which describes a motor vehicle of the convertible type having a folding-roof installation. The folding-roof installation has a plurality of moveable components, such as the main bow, the rear bow, the tonneau cover and various locks. These components can each adopt one or more positions in which the corresponding component prevents access to the vehicle or a part of the vehicle. These moveable vehicle components are not operated by hand, but rather by means of associated hydraulic actuators. The electromagnetically operated valves which belong to these actuatorsxe2x80x94if there is no electrical energizing current being fed to the said valvesxe2x80x94connect the chambers of the actuators to the hydraulic fluid reservoir. As a result, it is possible, in the event of a fault, to move the components of the folding-roof installation by hand.
The known drive assembly has an emergency operating mode in which the actuators can move freely, in such a manner that the actuators allow movement of the components of the folding-roof installation caused by an external force being exerted on the corresponding component other than by the actuators, in particular by hand. This emergency operating mode is desirable in particular in order to allow the folding-roof installation to be moved by hand in the event of a fault, for example a loss of electric voltage or a fault in the associated control unit.
U.S. Pat. No. 5,825,147 describes a motor vehicle of the convertible type in which the components of the folding-roof installation are operated by means of associated electromechanical actuators, the action of which is actuated by a control unit. The control unit is coupled to position sensors which detect the position of the moveable components, so that, for example, it is possible to prevent a collision between the moveable components. The control unit is also coupled to theft detection means, in particular in order to notify the theft detection means that the folding roof is fully closed or open.
Vehicles of the convertible type are often of striking appearance and also relatively expensive, and consequently vehicles of this type are undesirably often the target of theft of the vehicle itself or from the vehicle and/or break-ins.
The object of the present invention is to propose measures which provide improved protection against theft/break-ins.
To this end, the present invention provides a drive assembly which is designed in such a manner that, if this assembly is in the emergency operating mode and the moveable component is in a position in which the component prevents access to the vehicle or a part of the vehicle, and then the theft detection means detect theft or attempted theft, the emergency operating mode of the drive assembly is cancelled, and the drive assembly is then moved into a blocking mode, in which the free mobility of the actuator is cancelled and the actuator blocks movement of the moveable vehicle component coupled to it caused by an external force being exerted on the component.
The invention is based on the insight that the emergency operating mode, which is per se extremely desirable, often makes it relatively easy for a thief to gain access to the vehicle or a part of the vehicle, for example the boot.
The inventive idea is therefore to couple the theft detection means to the control unit of the actuator in such a manner that, if an (attempted) theft is observed, the free mobility of the actuator which is connected to the relevant component is cancelled and the said actuator is blocked, so that the component is also blocked and therefore cannot be moved (or can be moved no further) in order to gain access to the vehicle.
In the drive assembly which is known from DE 38 26 789, the invention can be realized by energizing one or more valves of the hydraulic system in the event of an (attempted) break-in so that the said valve or valves close and it is impossible for any hydraulic fluid to flow out of the actuator(s).
In the drive assembly which is known from U.S. Pat. No. 5,825,147, in which electric motors are used to drive the components of the folding-roof installation, the invention could, for example, be realized by short-circuiting the windings of the said motors or by making the motors operate in the event of an (attempted) break-in.
In an advantageous embodiment, the theft detection means comprise a position sensor which is designed to recognize the position of the moveable vehicle component and is at least designed to recognize whether it is leaving its position in which the relevant component prevents access to the (part of the) vehicle. This design is particularly advantageous if the position sensor is coupled not only to the theft detection means but also to the control unit for actuating the actuator.
In an embodiment which is simple in practice, the position sensor is a switch which is arranged on the actuator, which is designed to recognize whether the actuator adopts its position which corresponds to the access-preventing position of the corresponding component. If the corresponding component is then moved towards the position in which access to the (part of the) vehicle is possible, and the actuator coupled thereto therefore leaves its abovementioned position, the switch passes this fact on to a theft detection unit, which can determine, partly on the basis of this information, whether or not a theft is being attempted.
Particularly if a position sensor is being used to detect the theft, as explained above, it is also preferable for the actuator, in the blocking mode, to passively or actively drive the corresponding component towards the position in which access to the (part of the) vehicle is prevented. This is because the detection is then based on the component being displaced in the direction of the access-enabling position, so that a crack can already have appeared, into which a thief can, for example, place a piece of a tool.